With rapid development of a mobile communications system, the mobile communications system can provide increasingly high quality of service. To maintain a long-term competitive advantage of the 3rd Generation Partnership Project (the 3rd Generation Partner Project, “3GPP” for short) and further improve spectral efficiency and a user throughput of the mobile communications system, a carrier aggregation (Carrier Aggregation, “CA” for short) technology is introduced to the Long Term Evolution Advanced (LTE-Advanced, “LTE-A” for short) standard as a new technology. In the carrier aggregation technology, user equipment (User Equipment, “UE” for short) can simultaneously use multiple cells to perform uplink-downlink communication, to support high-speed data transmission. In the multiple cells, one cell is a primary cell (Primary Cell, “PCell” for short), and the other cells are secondary cells (Secondary Cell, “SCell” for short).
In a Long Term Evolution (Long Term Evolution, “LTE” for short) system, carrier aggregation may be classified into intra-base station cell aggregation, inter-base station cell aggregation, and the like. The intra-base station cell aggregation means: For one UE, all aggregated serving cells belong to a same base station. Because the aggregated serving cells are controlled by only one base station, the intra-base station cell aggregation is relatively simple. The inter-base station cell aggregation, also referred to as dual connectivity (Dual Connectivity, “DC” for short), is introduced to the Release-12 (Release-12) that is being developed. The DC supports carrier aggregation for multiple cells of two base stations, and therefore, a user can have better user experience. In the inter-base station cell aggregation technology, for one UE, one base station is a master eNodeB (Master eNB, “MeNB” for short), and the other base stations are secondary eNodeBs (Secondary eNB, “SeNB” for short). The master eNodeB bears more control functions and is generally a macro base station, and a secondary eNodeB is generally a micro base station.
Popularization of smartphones is accompanied with stricter user traffic requirements. Densely deploying micro base stations is an effective method for meeting the stricter user traffic requirements, and is also a future trend. However, in a current communications system, a master eNodeB performs centralized management control on a cell, that is, the master eNodeB delivers a command to control whether to add a secondary cell, or control to add which secondary cell. Specifically, the master eNodeB delivers measurement configuration to UE. The UE reports a measurement report according to the measurement configuration. Then, according to the measurement report, the master eNodeB determines whether to add a secondary cell, or determines to add which secondary cell. Consequently, as cells increase, so does a large quantity of system signaling. Therefore, the base station may be overloaded and cannot process a large quantity of signaling.